Climate Change – what we know & consequences› Climate› VegetationRecent trends for Arthur, NebraskaManagement implications› Tools› Decision support systems

Charles David Keeling

1928-2005

2002 Nat’l Medal of Science

Annual cycle due to photosynthesis and respiration of soils.

Long term trend due to emission of fossil fuels

IPCC Working Group I Report, Chapter 2, 2007

WHAT WE KNOW: Ice core sampling & other techniques indicate rising CO2 in Earth’satmosphere is a relatively new phenomenon.

Nutrients, H2O

CO2

Food, GloriousFood!

Any change in light, water, nutrients or carbon dioxide will alter plant growth.

Responses of plant functional group NPP to CO2 in the Colorado shortgrass steppe

Morgan et al., 2007. PNAS104(37):14724-14729

Responders & Mechanisms:

C3 vs. C4 photosynthesis

P. smithii seedling recruitment

A. frigida photosynthesis, soil water

40-fold increase inArtemisia frigidabetween 1997 & 2001!

Honey locust tree islands in Kansas Tallgrass Prairie.Present-day encroachment?Fire removal, climate change, CO2?(photograph courtesy of Alan K. Knapp).

Mesquite encroachment in SWover past two centuries

(photograph courtesy of ARS Jornada Experimental Range photo gallery).

WHAT WE KNOW: Global average surface temperature has increased 0.74 C (1.2 F) in the last hundred years. Rate of warming has doubled in the past 50 years.

Predictions indicate future accelerated & extreme warming.

IPCC 2007: WG1-AR4

Epstein, Gill, Paruelo, Lauenroth, Jia and Burke. 2002. J. of Biogeography 29:875-8

Modeled Future Relative Abundances (shrubs, C3, C4) in Grasslands of N & S America. Based on: • GCMs • Relative Abundance Equations

precip, temp, soil water

Based on observations & measurements obtained in the real world.

Approach does not capture CO2 response

Functional Plant Group Modeling

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1970-1999 2010-2039 change1 2040-2069 change2 2070-2099 change3

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Period

Arthur, NebraskaPeriod-Mean Annual Temperature

ukmo_hadcm3.1.sresa1b

ukmo_hadcm3.1.sresa2

ukmo_hadcm3.1.sresb1

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2006 2007 2008

Prairie Heating & CO2Enrichment (Cheyenne)

c (current) & C (high) CO2t (current) & high (T) Temp

Heat can diminish CO2 benefit

C3 g

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2006 2007 2008

Prairie Heating & CO2Enrichment (Cheyenne)

c (current) & C (high) CO2t (current) & high (T) Temp

Heat can diminish CO2 benefit

High CO2 & temp favors C4

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1970-1999 2010-2039 change1 2040-2069 change2 2070-2099 change3

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Period

Arthur, NebraskaPeriod-Mean Annual Precipitation:

ukmo_hadcm3.1.sresa1b

ukmo_hadcm3.1.sresa2

ukmo_hadcm3.1.sresb1

IMPLICATIONS OF WHAT WE KNOW Longer growing seasonDesiccation due to warmingAltered hydrologic cycle

atmosphere holds more water vapor intense rainfall eventstiming (altered seasonal precipitation;

earlier loss of snow pack)some regions more drought-prone

Plant Species Change

Photo: Sam Cox

What About Weeds?Will climate changefacilitate invasion?

CC decreases suitability for native species

1) High seed production2) Effective dispersal3) Rapid growth4) High plasticity5) Rapid evolution

Dukes and Mooney 1999, Trends in Ecology and Evolution 14:135

http://www.hprcc.unl.edu/maps/atlas/index.php?product=100&type=c&p_option=13&action=viewmap

http://www.hprcc.unl.edu/maps/current/index.php?action=update_product&product=TDept

http://www.hprcc.unl.edu/awdn/soilm/index.php?station=a250369&plot_type=soilm&year=past&action=View+Plot

The Hydro-illogical cycleReflective and Predictive Web-based productsDecision Support Systems

http://drought.unl.edu/plan/cycle.htm

http://www.drought.unl.edu/dm/monitor.html

http://www.cpc.ncep.noaa.gov/products/expert_assessment/seasonal_drought.html

http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/page2.gif

http://www.cpc.ncep.noaa.gov/soilmst/img/cas_w_mon.lead1.gif

http://drought.unl.edu/vegdri/VegDRI_archive.htm

Model InputsSite name:Ranch size:Animal type (e.g. cattle):Weather type (e.g. historical)

GPFARM-RangeModel

Forage forecastWeather forecast sources:e.g. NOAA, NASA, IRI, OTHERForecast: V. Good, Normal, Poor

Forage (kg/ha)

April June Sep

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Output

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2: Moderate

3: Low

Stocking and Forage demand rates:

- The interface (next slide) enables User to run the GPFARM-range on the web.- The model outputs the monthly forage production.- Depending on stocking rate, the output shows periods of forage surplus/deficit.- Ranchers can adjust stocks to minimize forage shortages.

Andales et al. 2006

Stocking Rate!!!Good Stewardship!!!Plan!!!Flexibility/Adaptivity of livestock operations will be paramount› Kind, type and size of livestock› Within grazing season modifications in number of

grazing animals› Movement of livestock across geographic areasPredictive power and accuracy will be essential for operations› Reduce risk!